Recent Polio Outbreak In Syria Threat To Europe: Experts

A recent polio outbreak in Syria and Israel could pose a threat to countries in the region and Europe, infectious disease experts warn.

Tourists and travelers could bring the infection to other countries, two German doctors said in an article published in the Lancet journal on Friday.

The risk is even more potent as hundreds of thousands of people are fleeing Syria and seek refuge in neighboring countries and Europe, says Prof. Martin Eichner of the University of Tubingen, and Stefan Brockmann from Reutlingen Regional Public Health Office.

WHO has confirmed at least ten cases of polio in Syria, where vaccination coverage has significantly decreased during the civil war. Furthermore, wild-type polio virus (WPV1) has been isolated from sewage and faeces from asymptomatic carriers in Israel since February. Precautions during the Hajj in Saudi Arabia in October ensured that visitors from regions with known polio transmission were vaccinated, but Syria was not on the list.

Because only one in 200 unvaccinated individuals infected with WPV1 will develop acute flaccid paralysis, the main symptom of polio, infected individuals can spread the virus unrecognized. Inactivated polio vaccine, which is used throughout Europe, only partly prevents human beings from infection, the doctors say. But in regions with low vaccination coverage such as Bosnia and Herzegovina, Ukraine, and Austria, herd immunity might be insufficient to prevent sustained transmission.

Vaccinating only Syrian refugees -- as has been recommended by the European Centre for Disease Prevention and Control - is insufficient; more comprehensive measures should be taken into consideration, the experts advise.

Oral polio vaccination provides high protection against acquisition and spread of the infection, but this vaccine was discontinued in Europe because of rare cases of vaccination-related acute flaccid paralysis. Only some of the European Union Member-States still allow its use and none has a stockpile of oral polio vaccines.

The doctors recommended that routine screening of sewage for polio virus must be done in European countries hosting settlements with large numbers of Syrian refugees.